A combined experimental-numerical study to tensile behaviour of limestone

In this paper, a combined experimental-computational study of double-edge notched stone specimen subject to cyclic tensile loading is presented. In the experimental part, the load-deformation response and the local displacement field are recorded. Both experimental results are used to validate a numerical model for the description of fracture within finite elements. The model uses displacement discontinuities to model cracks. These discontinuities are implemented using the partition of unity property of finite element shape functions. In the discontinuity, a combined damage-plasticity cohesive law is used. Numerical simulations are compared with experimental observations

Mobile health apps : an exploration of user-generated reviews in Google Play Store on a physical activity application

Objective This study aimed to evaluate reviews that have been posted publicly on the app ‘MapMyRun’ to investigate which features were associated with usage of the app. A secondary aim was to determine whether MapMyRun consisted of specific behaviour change techniques that would have increased the likelihood of users being engaged with the app. Methods Reviews posted on MapMyRun by users between 1st May 2017- 30th April 2018 were extracted, coded and analysed using content analysis. Results Eleven behaviour change techniques were identified among the features of MapMyRun. A total of 3,253 reviews met the inclusion/exclusion criteria, and 12 codes were developed. The codes were grouped into 8 subthemes within 2 main themes: ‘Effort’ and ‘Self-monitoring’. Consistent with previous literature, ‘Goal-Setting’ and ‘Self-Monitoring of Behaviour’ were two techniques included in MapMyRun. Social features of MapMyRun facilitated competition among users, their family, and friends. Conclusions This was the first qualitative review to assess a single mobile health physical activity app and analyse it from the perspectives of the users. Creators of future mobile health apps should focus on user friendliness and the use of social features, as both may increase the chances of users’ continued use with the app

Impact of the June 2018 Saddleworth Moor wildfires on air quality in northern England

The June 2018 Saddleworth Moor fires were some of the largest UK wildfires on record and lasted for approximately three weeks. They emitted large quantities of smoke, trace gases and aerosols which were transported downwind over the highly populated regions of Manchester and Liverpool. Surface observations of PM2.5 indicate that concentrations were 4–5.5 times higher than the recent seasonal average. State-of-the-art satellite measurements of total column carbon monoxide (TCCO) from the TROPOMI instrument on the Sentinel 5—Precursor (S5P) platform, coupled with measurements from a flight of the UK BAe-146–301 research aircraft, are used to quantify the substantial enhancement in emitted trace gases. The aircraft measured plume enhancements with near-fire CO and PM2.5 concentrations >1500 ppbv and >125 μg m−3 (compared to ~100 ppbv and ~5 μg m−3 background concentrations). Downwind fire-plume ozone (O3) values were larger than the near-fire location, indicating O3 production with distance from source. The near-fire O3:CO ratio was (ΔO3/ΔCO) 0.001 ppbv/ppbv, increasing downwind to 0.060–0.105 ppbv/ppbv, suggestive of O3 production enhancement downwind of the fires. Emission rates of CO and CO2 ranged between 1.07 (0.07–4.69) kg s−1 and 13.7 (1.73–50.1) kg s−1, respectively, similar to values expected from a medium sized power station

Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate

The aim of this study was to determine the extent to which oat particle size in a porridge could alter glucose absorption, gastric emptying, gastrointestinal hormone response, and subjective feelings of appetite and satiety. Porridge was prepared from either oat flakes or oat flour with the same protein, fat, carbohydrate, and mass. These were fed to eight volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma glucose, insulin, and gastrointestinal hormones were determined over a period of 3 h. The flake porridge gave a lower glucose response than the flour porridge, and there were apparent differences in gastric emptying in both the early and late postprandial phases. The appetite ratings showed similar differences between early- and late-phase behavior. The structure of the oat flakes remained sufficiently intact to delay their gastric emptying, leading to a lower glycemic response, even though initial gastric emptying rates were similar for the flake and flour porridge. This highlights the need to take food structure into account when considering relatively simple physiological measures and offering nutritional guidance

Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding

Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma. Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress. Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man

Exploring the use of adjusted body mass index thresholds based on equivalent insulin resistance for defining overweight and obesity in UK South Asian children

Background Body mass index (BMI) overweight/obesity thresholds in South Asian (SA) adults, at equivalent type-2 diabetes risk are lower than for white Europeans (WE). We aimed to define adjusted overweight/obesity thresholds for UK–SA children based on equivalent insulin resistance (HOMA-IR) to WE children. Methods In 1138 WE and 1292 SA children aged 9.0–10.9 years, multi-level regression models quantified associations between BMI and HOMA-IR by ethnic group. HOMA-IR levels for WE children were calculated at established overweight/obesity thresholds (at 9.5 years and 10.5 years), based on UK90 BMI cut-offs. Quantified associations in SA children were then used to estimate adjusted SA weight-status thresholds at the calculated HOMA-IR levels. Results At 9.5 years, current WE BMI overweight and obesity thresholds were 19.2 kg/m2, 21.3 kg/m2 (boys) and 20.0 kg/m2, 22.5 kg/m2 (girls). At equivalent HOMA-IR, SA overweight and obesity thresholds were lower by 2.9 kg/m2 (95% CI: 2.5–3.3 kg/m2) and 3.2 kg/m2 (95% CI: 2.7–3.6 kg/m2) in boys and 3.0 kg/m2 (95% CI: 2.6–3.4 kg/m2) and 3.3 kg/m2 (95% CI: 2.8–3.8 kg/m2) in girls, respectively. At these lower thresholds, overweight/obesity prevalences in SA children were approximately doubled (boys: 61%, girls: 56%). Patterns at 10.5 years were similar. Conclusions SA adjusted overweight/obesity thresholds based on equivalent IR were markedly lower than BMI thresholds for WE children, and defined more than half of SA children as overweight/obese

Prevalence of peripapillary choroidal neovascular membranes (PPCNV) in an elderly UK population—the Bridlington eye assessment project (BEAP): a cross-sectional study (2002–2006)

© 2018, The Royal College of Ophthalmologists. Purpose: There is paucity of data on the epidemiology of peripapillary choroidal neovascularisartion (PPCNV). Our aim was to determine prevalence of PPCNV in the elderly UK population of Bridlington residents aged ≥65 years. Methods: Eyes with PPCNV in the Bridlington eye assessment project (BEAP) database of 3475 participants were analysed. PPCNV outline was drawn, its area measured, and clock-hour involvement of disc circumference recorded. Location and shortest distance from the lesion edge to fovea were recorded. Masked grading for age-related maculopathy (ARM)/reticular pseudodrusen (RPD) within the ETDRS grid was assigned for each eye using a modified Rotterdam scale. Peripapillary retinal pigment epithelial (RPE) changes/drusen were recorded. Visual acuity (VA) and demographic details analysed separately were merged with grading data. Results: PPCNV were identified in ten subjects, and were bilateral in two (20%), a population prevalence of 0.29%, and 0.06% bilaterality. Gender-specific prevalence were 0.36% and 0.19% for females and males, respectively. Age ranged from 66 to 85 years [mean 76.3 (SD 6.4)]. PPCNV were located nasal to disc in 41.7%, measuring 0.46–7.93 mm 2 [mean 2.81 mm 2 (SD 2.82)]. All PPCNV eyes had peripapillary RPE changes. One subject had no ARM, 1 angioid streaks, and 30% RPD. No direct foveal involvement, or reduced VA attributable to PPCNV was observed. Conclusion: PPCNV were infrequent in this population, more common in females, and often located nasal to the disc, without foveal extension. Peripapillary degenerative changes were universal, and strong association with ARM was observed in eyes with PPCNV. Typically, PPCNV were asymptomatic with VA preservation

Overweight at age two years in a multi-ethnic cohort (ABCD study): the role of prenatal factors, birth outcomes and postnatal factors

<p>Abstract</p> <p>Background</p> <p>Childhood overweight/obesity is a major public health problem worldwide which disproportionally affects specific ethnic groups. Little is known about whether such differences already exist at an early age and which factors contribute to these ethnic differences. Therefore, the present study assessed possible ethnic differences in overweight at age 2 years, and the potential explanatory role of prenatal factors, birth outcomes and postnatal factors.</p> <p>Methods</p> <p>Data were derived from a multi-ethnic cohort in the Netherlands (the ABCD study). Weight and height data of 3,156 singleton infants at age 2 years were used. Five ethnic populations were distinguished: Dutch native (n = 1,718), African descent (n = 238), Turkish (n = 162), Moroccan (n = 245) and other non-Dutch (n = 793). Overweight status was defined by the International Obesity Task Force guidelines. The explanatory role of prenatal factors, birth outcomes and postnatal factors in ethnic disparities in overweight (including obesity) was assessed by logistic regression analysis.</p> <p>Results</p> <p>Compared to the native Dutch (7.1%), prevalence of overweight was higher in the Turkish (19.8%) and Moroccan (16.7%) group, whereas the prevalence was not increased in the African descent (9.2%) and other non-Dutch (8.8%) group. Although maternal pre-pregnancy body mass index partly explained the ethnic differences, the odds ratio (OR) of being overweight remained higher in the Turkish (OR: 2.66; 95%CI: 1.56-4.53) and Moroccan (OR: 2.11; 95%CI: 1.31-3.38) groups after adjusting for prenatal factors. The remaining differences were largely accounted for by weight gain during the first 6 months of life (postnatal factor). Maternal height, birth weight and gender were independent predictors for overweight at age 2 years, but did not explain the ethnic differences.</p> <p>Conclusion</p> <p>Turkish and Moroccan children in the Netherlands have 2- to 3-fold higher odds for being overweight at age 2 years, which is largely attributed to maternal pre-pregnancy BMI and weight gain during the first 6 months of life. Further study on the underlying factors of this early weight gain is required to tackle ethnic differences in overweight among these children.</p

Comprehensive Brain MRI Segmentation in High Risk Preterm Newborns

Most extremely preterm newborns exhibit cerebral atrophy/growth disturbances and white matter signal abnormalities on MRI at term-equivalent age. MRI brain volumes could serve as biomarkers for evaluating the effects of neonatal intensive care and predicting neurodevelopmental outcomes. This requires detailed, accurate, and reliable brain MRI segmentation methods. We describe our efforts to develop such methods in high risk newborns using a combination of manual and automated segmentation tools. After intensive efforts to accurately define structural boundaries, two trained raters independently performed manual segmentation of nine subcortical structures using axial T2-weighted MRI scans from 20 randomly selected extremely preterm infants. All scans were re-segmented by both raters to assess reliability. High intra-rater reliability was achieved, as assessed by repeatability and intra-class correlation coefficients (ICC range: 0.97 to 0.99) for all manually segmented regions. Inter-rater reliability was slightly lower (ICC range: 0.93 to 0.99). A semi-automated segmentation approach was developed that combined the parametric strengths of the Hidden Markov Random Field Expectation Maximization algorithm with non-parametric Parzen window classifier resulting in accurate white matter, gray matter, and CSF segmentation. Final manual correction of misclassification errors improved accuracy (similarity index range: 0.87 to 0.89) and facilitated objective quantification of white matter signal abnormalities. The semi-automated and manual methods were seamlessly integrated to generate full brain segmentation within two hours. This comprehensive approach can facilitate the evaluation of large cohorts to rigorously evaluate the utility of regional brain volumes as biomarkers of neonatal care and surrogate endpoints for neurodevelopmental outcomes